An antenna apparatus including a reflector having a concave curved surface, typically a parabolic surface, and a radiator arranged at a focal position of the concave curved surface of the reflector is widely known. In the reflector of such an antenna apparatus, a structural member such as a waveguide and waveguide mounting member is normally not arranged in a radiation space between the radiator and the reflector from the viewpoint of performance improvement, because the structural member could become an obstacle to emission or reception of a radio wave. Particularly, in an antenna apparatus for dual polarized waves, a structural member (such as a waveguide and waveguide mounting member) that could become an obstacle is arranged outside the radiation space, because such a structural member is an important factor of performance degradation.
In a conventional antenna apparatus configured as described above, it is necessary to design the reflector so that its stiffness is increased and also to design the structural member so that its stiffness is increased, in order to arrange the structural member (such as a waveguide and waveguide mounting member) in the outside of the radiation space.
In a technical field of the antenna apparatus, like in other technical fields, it is always required to reduce various costs such as manufacturing costs, assembly costs, and maintenance costs relating thereto in comparison with the conventional ones.